Composite eyeglass lenses have been formed by bonding together front and rear lenses, as suggested in U.S. Pat. No. 2,618,200. A device and method for accomplishing this has been suggested in U.S. Pat. No. 4,927,480. Generally, the bonding process involves placing a curable adhesive on the concave interface surface of the front lens; pressing the convex interface surface of the rear lens against the adhesive in the front lens, to spread the adhesive throughout the space between the two lenses; and curing the adhesive to bond the lenses together, forming a composite lens, which is then trimmed to fit within an eyeglass frame.
Especially when the desired composite lens includes a cylindrical component that must be properly oriented to correct for astigmatism and a bifocal or progressive focal region that must be properly positioned for reading purposes, the existing method and equipment have fallen short of the desired optical accuracy. Existing laminating equipment, for example, does not readily accommodate eccentric positioning and bonding of the front and rear lenses, which can be necessary in some cases. Also, existing methods and equipment have been inconvenient to operate and have put the desirable accuracies beyond practical reach for some composite eyeglass lenses.
I have discovered new and better ways of mounting, aligning, and bonding together composite eyeglass lenses to improve on the accuracy attainable. I have also discovered an improved way of mounting the rear lens on a holder and distributing holder pressure over the rear face of the rear lens, for evenly pressing it against the front lens and an intervening layer of adhesive during the bonding process. My method, practiced with my preferred apparatus, is also faster and more convenient, is easier to work, and produces fewer defects in bonded composite lenses.